


when we play, we don't cheat

by knightinbrightfeathers



Category: Shadowhunters (TV)
Genre: Adopted Sibling Relationship, Alternate Universe - No Powers, Alternate Universe - Non-Magical, Alternate Universe- No Supernatural, Background Magnus Bane/Alec Lightwood, Background Simon Lewis/Raphael Santiago, Banter, Bets & Wagers, F/F, Flirting, Gen, Getting Together, Jace Wayland is a Lightwood, M/M, Magnus Bane Being Magnus Bane, Sibling Love, Sibling Rivalry
Language: English
Status: Completed
Published: 2016-08-02
Updated: 2016-08-02
Packaged: 2018-07-28 22:41:48
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,918
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7659712
Author URL: https://archiveofourown.org/users/knightinbrightfeathers/pseuds/knightinbrightfeathers
Summary: <blockquote class="userstuff">
              <p>It starts and ends with a bet.</p><p>(based off this prompt from Shadowhunters Femslash Fic Exchange: clary/isabelle, my brother thinks you like him but my gaydar has never failed me)</p>
            </blockquote>





	when we play, we don't cheat

**Author's Note:**

> Thank you very much to s-lewis at tumblr for the wonderful beta work, and to http://shadowhuntersbetas.tumblr.com for matching us up. Also, thank you to pineapplebooks for setting this exchange up. It was super fun!  
> Title from "I Don't Do Boys" by Elektra.  
> (Also, in case it isn't perfectly clear in the fic: Jace was adopted by the Lightwoods and nothing hurts.)

“What do you think?” Jace asks.

Isabelle sucks on her straw thoughtfully. “Cute, but you don’t have a chance.”

“What? I’m so her type,” Jace says. He counts on his fingers. “Cool, hot, great dancer-”

“Emotionally unavailable…”

Jace scowls at Alec. “I thought you were less bitter now that you’re getting some.”

“It’s ingrained,” Alec says, high-fiving Isabelle.

“Whatever,” Jace says. “Izzy, come with me. You can dance with that guy sitting next to her.”

Isabelle shakes her head. “Uh, no. He has a boyfriend.”

Jace gives her a look. “Where?”

Isabelle nods to a man making his way through the crowd, beers dangling from his fingers. He’s wearing a blazer and a permanent-looking sneer, looking as different from the scruffy guy sitting next to Jace’s cute redhead as possible.

“Nah.” Jace turns to Alec. “He looks straight.”

Alec shrugs.

“Ten bucks says Sheldon Cooper over there is straight,” Jace says.

“Deal,” Isabelle says, holding out her hand for their secret-handshake.

Isabelle smooths down her dress- not that there’s much to smooth down- and turns to Alec. “You’ll be okay here?”

“It’s a club, Iz, not a war zone.”

“Plus, if someone hits on him at  _ my _ club, I will personally eviscerate them,” Magnus says cheerfully, appearing out of nowhere.

“You can’t say that kind of thing in front of me, I’m sworn to uphold the law-” Alec starts, but Magnus waves him away. 

Magnus sits down, somehow managing to lounge on a stool. “That’s why I said it behind you, darling.”

Isabelle and Jace exchange a look and make their escape before things start getting gooey. They’re old hands at weaving their way through a crowd, and soon enough they’ve reached the redhead and her friends, who are now bickering.

The redhead- Clary- smiles at Jace when he introduces himself, and Isabelle does find herself dancing with the nerdier of her companions. The way blazer guy- Raphael- scowls at her totally wins her those ten bucks.

At the end of the night Jace suggests they all go out together again. Clary gives both of them her phone number, blushing a little when her hand brushes Isabelle’s, even though they’d been dancing at much closer quarters earlier.

Knowing Jace, they’re never going to meet this girl again, so Isabelle doesn’t bother shutting down his gloating on the ride home. She falls asleep against her brother’s shoulder before she even remembers their bet.

-*-

“Welcome to Starbucks. What may I get started for you today?”

Isabelle blinks and pushes up her sunglasses. “Hi, Clary.”

Clary tips her head to the side with a frown before brightening. “Oh my gosh! Isabelle, right?”

“That’s me. I don’t think I’ve seen you here before.”

“New job. Gotta pay for that art degree somehow, you know how it is. Is it just you today?” Clary blushes. “Not that there’s anything bad about just you!”

“Just me,” Isabelle says, grinning. “My brother’s still working off his hangover.”

“And you’re not?”

“That’s what I’m here for.”

Clary’s expression immediately turns chagrined. “Right! Sorry.”

“It’s okay,” Isabelle reassures her. The soccer mom standing behind her chooses this moment to cough pointedly. Isabelle whips her head around to glare at her.

“I’ll just take your order. Uh, what would you like?”

When Isabelle gets her coffee, the cup has a little smiley drawn on it.

-*-

“Clary called,” Jace says. “Remember? The redhead from Warlock? The one you said wouldn’t be into me?”

“She isn’t,” Isabelle says, not looking up from her forensic pathology textbook.

“She just invited us to a Battle of the Bands thing.”

“She plays?”

“No, it’s her friend’s thing. The nerdy one, whatsit, Simon. It’s tomorrow.”

“She invited us both?”

“I just said that, Izzy-face.”

“And you still think she’s into you?”

“Yep,” Jace says, popping the p.

Isabelle pats his shoulder. “You do you, Jace.”

-*-

The Battle of the Bands turns out to be indie night at a local cafe, but there’s a nice atmosphere and the music isn’t all terrible. Simon and his band are actually pretty good for a garage band.

“You owe me ten bucks,” Jace says once ‘Rock Solid Panda’ are off the stage.

Isabelle glares at him. Most people would back away, but Jace just smirks at her. “Like hell I do!  _ You _ owe  _ me _ .”

“What, did you bet on their band being crap?” Clary asks, amused.

“At Warlock, Izzy said that your friends were together. She owes me ten bucks, because  _ obviously _ Simon and the singer are dating.” Next to Jace, Raphael looks like he’s bitten into a lemon.

“Simon and Maureen aren’t dating,” Clary says.

“Ha!”

“They had a thing last year, but it was pretty short-lived. I mean, he and Raph aren’t dating either...” Clary shoots Raphael an apologetic look.

“Pay up, Iz,” Jace says smugly.

“Wait, the bet wasn’t whether they were dating or not,” Isabelle says.

Jace ‘tsk’s sorrowfully. “Don’t be a sore loser.”

“The bet was whether or not Simon was straight,” Isabelle says, raising her voice over Jace’s.

“If he dated Maureen-”

“ _ Hermano _ , if you think dating the opposite gender makes you straight, you haven’t been paying attention,” Izzy says, tossing her hair. Clary, who’s been watching the argument like a tennis match, let out a small ‘ah’. “My gaydar never fails.”

“Give the guy his ten bucks,” Raphael snaps, startling them all. “Lewis is as straight as a trucker bar in Texas.”

“Uh,” says Simon, from behind Jace’s seat. “No I’m not? Hi.”

“Yes you are,” Raphael says.

“No, I’m definitely not.” Simon holds up a hand and swings it back and forth. “Swing Both Ways? We named the band that for like a month after I came out. It’s probably the name that lasted the longest…”

“That’s a terrible hint!”

“Am I supposed to plant clues to my sexuality?”

“Pink purple and blue’s clues,” Clary says, and ducks her head when everybody looks at her. “Pretend I never said that.”

“Bi-dvertisement,” Isabelle says.

Clary shoots her a grateful look.

“Guys, maybe take this outside?” Maureen says.

Isabelle looks around. The band’s joined them, and what with the crowd they’re making and the raised voices, there are quite a few people staring.

Raphael gets to his feet and leaves without a word. Simon runs after him a few seconds later.

With the drama over, everyone goes back to ignoring the awful banjo music onstage.

Maureen turns out to be fun, and the conversation flows so well that Isabelle almost doesn’t notice when Clary goes to order a soda and doesn’t come back. She finds Clary outside the cafe, chanting “pick up, pick up,” into her phone. When Clary sees her, she hangs up and smiles weakly. “Hey.”

“Simon isn’t answering?” Isabelle asks. Clary shakes her head. “I’m really sorry about before. It’s kind of my fault. Jace’s too, obviously.”

Clary laugh. It’s reluctant, but a laugh nonetheless. “It’s okay. This will probably be good for them. UST is a terrible thing, you know.”

“Oh, I know,” Isabelle says. “Remind me to tell you about my brother- my other brother,” she corrects. “He pulled a Made of Honor to get with his boyfriend. My mom almost killed him.”

“Isn’t that the one where the girl jilts her fiance for Patrick Dempsey at the altar?” Clary asks. Isabelle nods, and Clary’s eyes grow wide. “Oh my god. How old is your brother?”

“He’s twenty one,” Izzy says. “This was last year.”

“Oh, ew.”

“I know, right?”

“Now you have to tell me,” Clary says. She sits down on the cafe stairs and looks up at Isabelle expectantly. “Oh, wait, do you want to sit somewhere cleaner? Your dress will get messed up.”

Izzy smiles and sits next to her. “I don’t mind.”

-*-

“Who are you texting?” Jace whispers.

“Texting? James Christopher Lightwood, I am listening to this beautiful speech Senator Herondale is giving,” In her silk-clad lap, Isabelle’s fingers fly across the screen of her iPhone.

Years of boring embassy dinners and ceremonies mean Isabelle can text without looking down even once, although she still needs to read the replies once in awhile. And turn off autocorrect. (Other skills honed by the elder Lightwood siblings include lying through their teeth, faking smiles, and hiding pain au chocolat in designer purses and slim-cut suits.)

“Please, even Maryse isn’t listening to Senator Horrible.”

“Guys, shut up,” Alec hisses. “Mom’s looking this way.”

All three Lightwood siblings straighten up in their seats and pretend to be listening attentively until the ambassador’s keen eye turns back to the front of the room.

“I wish I was Max,” Jace grumbles.

“I wish you were Max too,” Alec says. “Then you’d be small enough to drown in the chocolate fountain.”

“You can still do that,” Isabelle says. She giggles quietly.

“It wasn’t that funny,” Jace says. Alec smirks at him.

“Clary is,” Isabelle says.

“Who’s Clary?” Alec asks.

“She’s texting you?” Jace asks. “I haven’t heard from her since last week’s show.”

“Clary’s the redhead from Warlock,” Isabelle tells Alec.

“Oh, her.”

“She texted you?” Jace pokes her until she smacks his hand away.

“Still think she’s into you?”

“She said she had a great time when we left the cafe.”

Isabelle rolls her eyes. “And she spent the entire evening with me. Face it,  _ tonto _ , she’s into me, not you.”

“No way. I’m telling you, she likes me.”

“She’s  _ gay _ ,” Isabelle says.

“And you know that how?”

“My gaydar never-”

“Never fails, yeah, yeah.” Jace folds his arms. “Fifty bucks says she’s into me.”

“Always happy to take your money.”

“You both suck,” Alec says, just as Maryse glares at their table. “Help me fake a heart attack to get out of here.”

All three fall silent as they consider this option.

“It won’t fly,” Isabelle says finally. “Statistically, the likelihood of you getting a heart attack is one to twenty five.”

“Nerd.”

“Dick.”

“Shh,” Jace says, and they both kick him.

-*-

“Hi Iz, what’s up?”

“Everything’s great. Are you busy?”

“No, just grocery shopping. Simon tried to make practice pancakes last night and he used all our milk.”

“What are practice pancakes?”

“Practice for when Raph stays the night and Simon makes him morning-after breakfast.”

“Raphael doesn’t seem like a pancakes person to me,” Isabelle says. She leans back into the sofa cushions and ignores the faces Jace is making.

Clary giggles. “He really isn’t, but he’s kind of gone on Simon, so he’ll probably choke down a few.”

“Would you?” Isabelle asks.

“Stop stalling,” Jace mouths.

“I love pancakes.”

“I know a diner that does great vanilla-berry pancakes.”

Clary pauses. “Is this what I think it is?”

Isabelle crosses her fingers. “Do you want to go out with me on a date? Just a date. No pre-pancakes activities necessary.”

“I’d love to,” Clary says.

Isabelle punches the air.

To Jace’s credit, he pays up with good grace.

-*-

“I don’t believe you,” Clary says.

They’re walking side by side, joined hands swinging. Isabelle feels like she’s flying, like she’s being serenaded by angels. It’s the best first date she’s ever had.

“I swear on all five hundred pounds of my textbooks,” Izzy says, and Clary giggles. “He really thought he had a chance.”

“But I’m-” Clary gestures with her free hand, trying to sum up the enormity of her gayness.

“I know,” Isabelle says happily. She grins at Clary helplessly. “Still, I can’t complain. He did bring us together. And he gave me fifty bucks.”

“I’d say you got a pretty good deal,” Clary agrees, grinning back.


End file.
